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Shop Compressor Air water separator.

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jcdammeyer

John
Premium Member
Finally got the leaky compressor filter/water separator apart.
1719904769519.png

Needless to say the Orings are a crumbly mess. Searching online I find I can get two Orings for about double the price of this:


1719904504084.png

Very sad. I'd rather repair it but what's the point?
 

Susquatch

Ultra Member
Administrator
Moderator
Premium Member
Very sad. I'd rather repair it but what's the point?

Surely there are better O-ring suppliers. Check out your nearest farm supply place.

Even so, your time is prolly worth more dancing than searching for oring suppliers.
 

jcdammeyer

John
Premium Member
Surely there are better O-ring suppliers. Check out your nearest farm supply place.

Even so, your time is prolly worth more dancing than searching for oring suppliers.
Very true. There are Aliexpress vendors who have packages of ORings for around $1 so I may go that route. But you are right. A lot of work. Mostly sentimental. It's from my first Sears 2HP compressor acquired now about 50 years ago.
 

Tecnico

(Dave)
Premium Member
I’ve been lucky at my local independent hydraulic cylinder repair shop/O-ring supplier. I’ve been able to buy small quantities & odd material rings through them vs a pack of 100.

Probably wouldn’t fly at one of the chain owned shops though.

About the separator “bowl”, have a close look at the molding to make sure there aren’t any cracks. I’ve had a couple PA units fail that way (seeping).

D :cool:
 
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jcdammeyer

John
Premium Member
I’ve been lucky at my local independent hydraulic cylinder repair shop/O-ring supplier. I’ve been able to buy small quantities & odd material rings through them vs a pack of 100.

Probably wouldn’t fly at one of the chain owned shops though.

About the separator “bowl”, have a close look at the molding to make sure there aren’t any cracks. I’ve had a couple PA units fail that way (seeping).

D :cool:
The bowl is fine. It's the compressed dried out rubber that is tightly stuck to the plastic and crumbles when it's removed. So I suspect it's been leaking for quite some time but with me bopping around the system probably bumped it a few times dislodging it enough so the tank that would cycle the compressor every 4 to 6 hours would take it down in under 2.

With it removed it holds pressure for a really long time so the rest of the system is in not bad shape.
 

Stuart Samuel

Well-Known Member
Premium Member
Hey John, you could check Princess Auto, as Tom O suggests, and you might get lucky on diameter, or maybe make up an o ring to suit? You can buy spools of o ring stock from a variety of places, maybe somewhere your way will sell to length?

I don't know how they do under extreme pressure, but I've had good results just super-gluing the damned things together at the ends (there are rubberized cyanoacrylates that'd probably be good for this). If you're in a pinch, let me know what diameter stock you need, and I'll check the spools we have at work and stuff some in an envelope, if there's a reasonable match.
 

jcdammeyer

John
Premium Member
Hey John, you could check Princess Auto, as Tom O suggests, and you might get lucky on diameter, or maybe make up an o ring to suit? You can buy spools of o ring stock from a variety of places, maybe somewhere your way will sell to length?

I don't know how they do under extreme pressure, but I've had good results just super-gluing the damned things together at the ends (there are rubberized cyanoacrylates that'd probably be good for this). If you're in a pinch, let me know what diameter stock you need, and I'll check the spools we have at work and stuff some in an envelope, if there's a reasonable match.
Thanks. That brings up an interesting question about sizing O-Rings.

The shoulder is about 0.088 deep and high. The diameter of the seat is about 1.87" Just a rough measurement.

Does one get an O-ring with a material radius of about 0.088" or closer to a diameter of 0.088" and how large? Does one select 1.87" or 1.87" plus the rubber radius or maybe minus the ribber radius to allow some stretch?


1719974901388.png
 

Tecnico

(Dave)
Premium Member
Thanks. That brings up an interesting question about sizing O-Rings.

The shoulder is about 0.088 deep and high. The diameter of the seat is about 1.87" Just a rough measurement.

Does one get an O-ring with a material radius of about 0.088" or closer to a diameter of 0.088" and how large? Does one select 1.87" or 1.87" plus the rubber radius or maybe minus the ribber radius to allow some stretch?


View attachment 49313

O-rings are typically sized on dimensions of the gland and cross section of the ring. On a well defined gland like a hydraulic cylinder it’s easy to measure the gland and suss out what the O-ring size should be. OD, ID, Width etc.

For yours they might have fudged things a bit for dimensions but they may have stuck pretty close to the book sizes, a bit of measurement should help you zero in on a probable size.

For the book size you want to go to something like the Parker O-ring Handbook (download the pdf or request an hard copy to know more than you’ll ever want to know about O-rings!) and check out the gland dimension tables. They will conform to the AS-568 series dimension in @slow-poke ’s table.

Notice that there are tables for various gland types - e.g. there are face seal, internal and external groove types. They tweak the gland for the use type. It’s a bit of a read but ‘way easier than deciphering all that electronic stuff you’re good at and puzzles me, lol! ;)

When you’re picking, make sure the material is good for the oil that’s in your compressor, some materials aren’t so good for mineral oil.

More than you ever wanted to know?

D :cool:
 
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jorogi

Ultra Member
The bowl is fine. It's the compressed dried out rubber that is tightly stuck to the plastic and crumbles when it's removed. So I suspect it's been leaking for quite some time but with me bopping around the system probably bumped it a few times dislodging it enough so the tank that would cycle the compressor every 4 to 6 hours would take it down in under 2.

With it removed it holds pressure for a really long time so the rest of the system is in not bad shape.
There is a hydraulic cylinder rebuilder just around the corner from you I believe, that is if you are where I think you are. He's in the industrial area just above the Butler pit. Can't recall the name but I have a cylinder I need seals for, he helped me out on one a couple of years back, good guy. I'll try for a name.
 

mickeyf

Well-Known Member
Another vote for VP Systems. They were the only ones on the south island that had the part I needed to fix a cylinder on a large bandsaw some years back.
 

jcdammeyer

John
Premium Member
Another vote for VP Systems. They were the only ones on the south island that had the part I needed to fix a cylinder on a large bandsaw some years back.
It's on my list since I really don't want to throw it out. But I also want to clean it first. Haven't had time for that just yet.
 
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